SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e67a6f7fed540537cf19515cd24cfd0882834094a86f877bf2bb0fecabc29400' 
  AND token = 'yXK73MgFWsB3cO4CKHHpzljQ27J1YJEXha09GmGVDVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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