SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68c566f70656e2204fb0f22c5583d594c5f492271d73239f0f315f57a79e4c4b' 
  AND token = 'rj/h4ZYx67dDkfmUlYM81DDP/qUm1JhHKiNZL8BJWVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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