SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '066c03296b90169614c82afb82733d57b402ae6cc6bee6cd2a61010f0426f128' 
  AND token = '2v7wVFZA2xtPCNqvQRU1uPvxpHkBye5uPTAd4kJAxI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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