SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efb7731e08cc2c762630a2813ff5805f7bb66b3f1811a39b93197854a31e2df4' 
  AND token = '8MtGlD5mhEEJH+bZkWLXf6QK+Bq6y1lRJHkV9BSVOcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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