SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f7bbb5299e4c00b85893d8e5179087d08286f024dbc20978752bec218d72e21' 
  AND token = 'ZgzqJwUBH7GWgzDC6H2koDJt79mPktErsy2HaU5VSKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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