SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3b66a635c8ec91280ffbf90225437f914e1490de49b40bfcd8dc00b7b5354c6' 
  AND token = 'zREoaw+Y53SYwL6E4celWqAPExqxZMJljX/nBUUxmXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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