SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5eaaca5d8b82b5f92820b9fd5aa1dc99bb473a720a5ccf29a7b7b85fa1fdbe07' 
  AND token = 'MKlaQlrI9cG7HT22lnUFdk73T/FDnYTEtkLrzoKBwxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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