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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8c9dac8f7d7ba5b87c214494d3c93db2840baf447883716ef0c656ff3a5d860' 
  AND token = 'bM6dcgdicuavhkA2L1ZDwqMELFNIe2qBvmo7Lvkcvxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}