SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67373ab85dfdf4e781a5ea0f996e1e522d690d64eedf70bdb983ab592c3ae973' 
  AND token = 'IKp2j8axY/RsKpRJ/MmORBHSfm/BEranqFBPMMazstQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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