SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a42c652ba87073cc19971edd66c7a615f05d6479bb30f78dec0e9d199374e406' 
  AND token = '0E7x66NDNlp4zL5BgIo+KwJHrgGq4ZFvRHPm6MYsrvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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