SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c2909162e773cd7b9846ed4641b3a89d54357e10f8375a6a4ab2cb03b52c5f5' 
  AND token = 'PiyAdHd9nlCoY0ZFMDRP9SFycYXppfq9EKUdtTGyXpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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