SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81cd6f47d7cdc6e9d4e9fe3414ec99091cb6f90edd776e798c27270053380754' 
  AND token = 'sWxNoEBBpCpYg3U/LwL6Qo8R6YUuKgybf0MHIEebGGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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