SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e47fdccabad1cae114419fde56f9d70fe15618ced4160b5a4c7d4ebab36d417' 
  AND token = 'CVomAgpfti1mVFc9dNXN0AeUt/NQPLwhKZeT4venF5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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