SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4a3753ee72ef0b7853bf3650325fb62da28d469b62e031c74a2068a9a63b214' 
  AND token = '+fE8MvZMM/ouKVuKzKuQc9Ss1uB6dnurjq4DZ1ybVYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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