SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c733494433737600f3bf29f3ca5d94baeb2d425c19ef5b95a9cbe9465dc1ef5' 
  AND token = 'nB9Qdj1khuNsD4gz9v+1ZeKdqE+5b7FqpPSo38x04Bc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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