SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2933513d459022e17ca923a0346d8e55e646580c08b8667c8d8371a37a3a8fa2' 
  AND token = 'CYE9wucJA1ztqVwuMmZuYhYPOKzrC6BE98ZIV+sesYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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