SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3f1bd79fea53c6d45ffe9050e8692ea3b1a7d998b67eb70d8558226caaff9cb' 
  AND token = 'dYv2b8qtCzRJmBw/Tq4ivFGMUpvcB4CNbJV60qeyPAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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