SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77f3fd48d09069841dccc647e62426cd60d14008eeb85587ae1c5234a3a4cda0' 
  AND token = 'pX5oPFcUKoRTIH5ZqJeD0uN3L2VzPPt2Bf/ofPiYtM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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