SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a14b8076099ef08d8386f5798d54d7b5d09ea1ad8a9048d17e47b3d61c622274' 
  AND token = 'dPeEnNOcK0ZGUx+u9ymejwvBlsRzjox+d6rVoufEb5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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