SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38d7844bd64812389ab66aea098c91fecc5cf455282db35ce07a130fca8d0733' 
  AND token = '6QfzWGf/tw5pBtxr1HSPj1/rvvTgvqnz+1F70njci/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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