SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3197a8bce68c45575950df5e80754fe7affbc559b9d6a67befb59992ef64dcd7' 
  AND token = 'uooNxOmAdYycNAKsdD1vTUKx3WhPfAlnfNbo8n0cMgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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