SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cd67b861af5a1efa5fe9d480ebfeec9fd056afb6062d875a9fba2e4274a0674' 
  AND token = 'tXh+X87jjqy/pthoJKacOLxiTLqqD8OHaGq6UaYMKm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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