SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a66cf48963ac2a63563aefaf564a91d487f2688ef13a07cc522721273d34d1ba' 
  AND token = 'hoMuW6ubsuyqJXsjUMXUPgUac+IIezt9QHkVwOJH/qA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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