SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53bbb81f2f847a333caa567f95e2918f9d6fee6a3e8553c8b342db37a5e229ed' 
  AND token = 'FpTOqtr2nZPjc0bGk5LwZwaM+i3btW14+pAUjz8VYDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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