SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6fa77ef2bddc521c76795435990064367d32cb1b673f0cb67dfc50a178e88e0' 
  AND token = 'iHRJid3KZvFipt3t0oFKZi2i6cgOEziMfpYYVxceUDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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