SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cf3595b114271198a4243ce2ee1873b1b5b90b57aaee9555d59859259afcbda' 
  AND token = '8ogc7+a6DF23wkOxLPvKkyaUcftmLCaBtLaQWEaA6bY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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