SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4437e5aef84737ffd056ebc70f47ff89f31554985bbb5ee254d3123ccc541176' 
  AND token = 'uZfJ4RKN2wC/+shfgjXAcfKUZIwVtvWxgkuO9SZh5vU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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