SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfcdfeb11cc60470feb86abf1c9ba3c3c5903d97dae70d472c676b77db95820f' 
  AND token = 'S/NEWd5UjmUzbhDNNVHWDJ12Q2esa7+BhsfGpNfI2uU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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