SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e3432f8f525e4dc6ae196619f9aab73b09d1bc2f57547946b17edf0981eb0e3' 
  AND token = 'A0qmI5Nn1mkEGuvbFfRy5DSla1QNtnpiWZL1C21irU8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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