SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ff41f096d4b966b54c906d55a518100ff39ae82979bf09c7a03b6267e3edef7' 
  AND token = 'KdWJnhiA/Qsg0vX/wF9a94TGrpqeL1pawSYxURuvuP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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