SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f31d533ccba5f2b6efa13b23748a8e4fd4a134cbeb86c03ce4f279a3fb289a6' 
  AND token = 'vY2QRJSpqXjYSqrkL5AiC+GU9BUz6rV91gFiw3ZwYbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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