SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3810454eb4bb66f4d46f9880075707035d32ee41662cad7a867f200e5c4c636' 
  AND token = 'XSBZ2qtVlDGBK4mLRZTkklu5CUovWioYV5RCSJM2AjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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