SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac281b6f57920d8de4ad79833290adbbe3b79981ec691d0e4ba8fe112b07d66a' 
  AND token = 'eDMxLFrxaCWYCu3PUHv5s2sHjKqGGjSJ+eOLZ0eyzYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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