SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c35ce52097485c2bdc747813bbb5ba98e5c7f6874bea122fbb1a93bbddf72506' 
  AND token = 'SmLYbCLwbLJtaqxKIk8JdpkarVlbpVLDNCouVuoegtc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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