SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e41c215274c92852825534f73922d510888d673066b0a185968cfbd4e45c269' 
  AND token = 'AnaDwJAmos1STrpLxeLUJWbhGVZJUjq91q6qZ1K+xlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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