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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc1f9ca2e3346af1c92650b5b02cb92d75a3fd63ad13ed328f1c5cfd1393e286' 
  AND token = 'zFLv9HQoBAr8NXGB9kcnkz0RzXTOPYdqZn1P41lznlE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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