SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7aff8e55346b9057ffa2f360c052bfd14023b90cdd271aa370693eef72509ee' 
  AND token = 'MDy+kp+RaTNwMj8j/MheyjWs1fqBy3zk9jhqcdYWBjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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