SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bf10366d785c5e7e422154c2b5e633a991b3256820f0400a24c3e7138fa021f4' 
  AND token = 'EmrZte7hGrOKAO8MGhYgCd/cdQBkXTgy+i8p/7QimRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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