SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4db30c4faa27a30ce25aeac5e2bb7acbc51938fc7b8b09a1cc647caa74f5b730' 
  AND token = 'yjSLVL50ZzrICXKvglzoZP0hkvkvfSVOxpipG/5soOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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