SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79d72a72b533b9450f7dbc5f56941efea00c072674104fc2fcedc3728c307dec' 
  AND token = 'JGR9N6FocTxhpgY9uiY+uFIN7wHNL47DS2G4fqZeoVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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