SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fa26255da719603bf7dc5b3fec3cf1585faa49729eee88d48cf158b5da63d37' 
  AND token = 'hgXazuBT1ajfldz4CO56EDhrmGZKEKllog/rNRICj1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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