SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f8159f6121010da9eca61120796309c120b978df87a27a84d7deb5bc0ffa2c4' 
  AND token = 'M5CAzyTPChQmCDU1xWDvgLNHmUfITVqmqGrFgAob0EE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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