SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b20b182bf1d84839579f2006f11a08a0a2cb254002578ba375a6fdb5bc17976' 
  AND token = 'vGIm/0Sjfvl3Q6YTJoMrWKnpbCstfgiGZtZKUO0f+4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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