SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcc4236ad40b164f7cb52b0f1098c21798ed49267acb735b7527d2875537d2b0' 
  AND token = 'PEOYXkLR6agkIoe9Fiw8yRU1ZBZ78ciQ5u4odFPHoRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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