SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '262977074a94c4f480e9a64fed60e704399b7044f68c5dd943edc60389e42924' 
  AND token = '8njpmSPRLKcFTL/z4kazeXnUEtkizP0wIClnfgWufNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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