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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bb7686dfc7f2fc2a49a2d431f1ab16e7a93b08c936f8ebfd1e42a4c61c17a82' 
  AND token = 'x5L6DW/kUmwYvrdFn2508XXUxulL62OGs4q6/wwxqXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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