SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '76dc3764ffd43b16781f1b105e8bb671d6914e172908e331af26db1ca5802a6e' 
  AND token = '8j0rJNdxweIL+yDjAXRkqmFsqpoVkhYA4iIbKgU3LR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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