SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f48b19b5fdc047380589f86e5cbe844678017ab2ccdbf87542d32f06b472a21' 
  AND token = 'KzvVclGjOqvZJDtHUTf7YwWcGdnxcnk2gPpKWubIHmw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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