SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd4716ebf0bb5f4a5f0fde16aa2bd8990a8667f29eed9dca3b56c31595685f29a' 
  AND token = '4k5Zk6Hb2ZX9P/Q2qMPYhR1tiD5GgKwxsS+MJNnkwDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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