SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5caa7ff82b929d7f9376c0e41cdf0463f07337af4f0b93985f706a49fa4ec21' 
  AND token = 'VqKf50ZdTbwYE9tTioA3b0UXyWBHippmlha3RJIgYIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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