SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69ac55b84a80bc28275bb88b1f2c7dee8e3ae7c57d87b1256f211046f815dbe4' 
  AND token = 'tFD0I9dIv2S3FjSTEGk4PNzCRxHJ/XG2Nh2zbUsv2+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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