SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c033863da861dd43afcfd92b68f8f0ff094ce7a8d1f21f0e9865461053c75d5' 
  AND token = 'Mh/OizCB0N+TU4dUC9xtno/FYZ+ELZ0ufimrSzmkPgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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