SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e92c5b7e1deba57a0b027b1e93bc584d1f61bdd956662ada04a644bcc3083b1' 
  AND token = 'Dxo2saoDvavmcbl8DLTiFuzwDnG+JPuGTWBgUMDPvyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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