SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b011f5137858364c4b0af741889fde46456e15a301c66edfe33a3834a5a1b897' 
  AND token = 'CWBfJTMdkEDaBv7vJ6yIe5jO3sAD8q9lKEKQ8g6bGpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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