SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f269bf7e21b64aed28a1bede005089117aedb80e46f52f7eb5107454dd0bbf43' 
  AND token = '9vqgyrApoU1pKti2LbJALbE+JFWx55p5DsNmwVRkS1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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